1. Field of the Invention
This invention relates generally to window structures and, more particularly, to a protective shield covering the window structure to provide a thermal barrier.
2. Description of the Prior Art
Modern glass window structures are usually made with an extruded metal frame, usually of aluminum, which supports a glass unit such as a window pane or a Jalousie window, at its perimeter, and lends strength and rigidity thereto. When used in situations where there is a large difference in temperature at opposing sides of the window structure, such as a Jalousie window mounted in a wall of a bathroom and subjected to an outside freezing temperature, the glass portion of the window and the supporting metal frame conduct an excessive amount of heat from the warm interior of the room to the outside freezing temperature. Furthermore, there is a tendency for the moisture inside the room to condense and freeze on the inner surfaces of the window and on the metal frame.
Many approaches have been made for solving this problem with various designs of storm windows. For example, U.S. Pat. No. 2,191,500 describes an arrangement for adding an additional window pane which is supported by frame members mounted by screws to the window frame. This type of securement makes it difficult for the window pane to be removed for cleaning purposes or for permitting airing between the interior of the house and the outside.
Another form of a storm window is described in U.S. Pat. No. 4,121,379 wherein an additional window pane, peripherally supported by a frame, is attachable on the inside of a regular window by means of a plurality of turn locks. This type of securement also requires some effort for removal of the additional window pane.
A still further arrangement for a storm window is disclosed in U.S. Pat. No. 4,069,641 wherein a tape frame is mounted on the inside of the periphery of the regular window, the tape frame being provided with means for securing a glazing frame so that an additional window pane may be secured between the tape frame and the glazing frame. Again this requires considerable effort to remove the additional window pane whenever it is so desired.